Question
Chemistry Question on d -and f -Block Elements
Four successive members of the first row transition elements are listed below with their atomic numbers. Which one of them is expected to have the highest third ionization enthalpy?
A
Vanadium (Z=23)
B
Chromium (Z=24)
C
Iron (Z=26)
D
Manganese (Z=25)
Answer
Manganese (Z=25)
Explanation
Solution
The third electron extracted during the third ionisation enthalpy belongs to the third-subshell family. This indicates that although the shell and subshells of all elements are the identical, the quantity of energy needed depends on the stability of the d-subshell. Mn thus has the greatest third ionisation energy.
Therefore, the correct option is (D): Manganese (Z=25)